Cardiopulmonary baroreflex is reset during dynamic exercise

Shigehiko Ogoh, R. Matthew Brothers, Quinton Barnes, Wendy L. Eubank, Megan N. Hawkins, Sushmita Purkayastha, Albert O-Yurvati, Peter B. Raven

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Abstract

The purpose of this study was to examine the hypothesis that the operating point of the cardiopulmonary baroreflex resets to the higher cardiac filling pressure of exercise associated with the increased cardiac filling volumes. Eight men (age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg; means ± SE) participated in the present study. Lower body negative pressure (LBNP) was applied at 8 and 16 Torr to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak oxygen uptake (104 ± 20 W). Subsequently, two discrete infusions of 25% human serum albumin solution were administered until CVP was increased by 1.8 plusmn; 0.6 and 2.4 ± 0.4 mmHg at rest and 2.9 ± 0.9 and 4.6 ± 0.9 mmHg during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, forearm blood flow and cardiac output were measured. During exercise, forearm vascular conductance increased from 7.5 ± 0.5 to 8.7 ± 0.6 U (P ± 0.024) and total systemic vascular conductance from 7.2 ± 0.2 to 13.5 ± 0.9 l·min -1·mmHg -1 (P < 0.001). However, there was no significant difference in the responses of both forearm vascular conductance and total systemic vascular conductance to LBNP and the infusion of albumin between rest and exercise. These data indicate that the cardiopulmonary baroreflex had been reset during exercise to the new operating point associated with the exercise-induced change in cardiac filling volume.

Original languageEnglish
Pages (from-to)51-59
Number of pages9
JournalJournal of Applied Physiology
Volume100
Issue number1
DOIs
StatePublished - 1 Jan 2006

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Keywords

  • Blood pressure
  • Central blood volume
  • Forearm blood flow

Cite this

Ogoh, S., Brothers, R. M., Barnes, Q., Eubank, W. L., Hawkins, M. N., Purkayastha, S., O-Yurvati, A., & Raven, P. B. (2006). Cardiopulmonary baroreflex is reset during dynamic exercise. Journal of Applied Physiology, 100(1), 51-59. https://doi.org/10.1152/japplphysiol.00804.2005